having the hammer snag on a draw can ruin your whole day...so can having the gun not fire. And if it doesn't fire, a smooth snag free draw is kind of negated, now isn't it?
I'm not a fan of bobbed hammer guns, and won't pay for one, unless it came that way from the factory. Not because bobbing the hammer always renders the gun unreliable, but becuase it might.
Different ammo has different primer hardness/sensitivity. Factory guns are set up to ignite the wide range likely to be encountered. I'm sure there is a certain amount of "extra" force factored in, just in case. Change the hammer, and you have no idea if you have removed this margin, or not.
The gun may work reliably for ages, until it does not, when an extra hard primer happens to be under the hammer. Or it might start misfiring right away. No way to tell, that I can see. Your gun, your call. Not for me, thanks.
I have had one bobbed hammer gun, and it would reliably fire, 3-4 rounds out of six. And not the same ones every time, either. You do what you want, and so will I, and we'll get along fine.
Remember that if you ever decide to sell the gun, to get full value, you'll need a buyer who thinks like you do, because to me, you butchered it....
All else being equal (and it almost never is) bigger bullets tend to work better.